our club fishes a lot of small lakes. so we don't do a lot of running with the big motor and my battery runs down and wont start when it needs to. in fact, it gets so low my power pac wont even jump it. do I need a bigger battery or a deep cycle that can handle the load?

 my OB is a 150hp and my battery charger is a 3 bank that I use every time I come in from a day on the lake.

 

Get a X2/Northstar 31 AGM, I've got four in my boat, zero issues running Solix 15 and 360 all day.  Deka is another good brand, their Intimidator 31 series AGM.

 

Whatever you do, stay away from Interstates....

Need a lot more info.  What battery are you running now, what are you running it on, how old is it, how do you charge it.....It's always a safe bet to go bigger .......but........ why is your cranking battery going down?  The only thing that should be hooked to that battery is your graphs, pumps and lights.  

currently using a size 24 battery and running 2 elite 7 units plus aerators. use a 3 bank charger and the battery is 2yrs old

 

 

Sorry to hear you say that about Interstate.  I only have to crank a 60hp, and had a size 24, 800CCA on it for nine years before it gave it up this spring.  I do pull the battery in the winter and keep it on a tender with a desulfinater all winter. The Interstate dealer could not believe it when I turned it in for a new one.  It also runs two sonars.

Been there @hoosiergramps more times than I’d like. Nothing like being on fish with a live well full of ‘em, go to start the big motor to head on in and crickets.... Pulling  a trolling motor battery to connect to start the big motor is a temporary solution for the immediate problem. I went with the best AGM battery available AND a Perko switch to cover my bases.  Good luck and good fishing, JB 

I use Northstar AGM 31's.  They're pricy, so take a deep breath before looking. But they're beasts.

 

 

Optima Blue top.

M31.

A-Jay 

I've ran 29 series everstart from wal mart for years and years. Usually get 6 years from em and they're cheap. I also fish small lakes usually and dont run a lot. Are you keeping in on a charger when not in use? Before I went to a 3 bank and kept cranking batteries on charge as well as trolling I had similar issues. 

I'd move up from a 24 series to the largest one that would fit in the boat.  Be sure to get a good amount of CCA and or MCA.

On April 23, 2019 at 8:24 AM, hoosiergramps said:

currently using a size 24 battery and running 2 elite 7 units plus aerators. use a 3 bank charger and the battery is 2yrs old

 

 

As Toxic said need more info.

Let me guess you fish local bass tournaments and run the Sonar units and aeration system constantly. 

1. What OB engine are you trying to crank, 150+ hp?

2. 3 bank charger, 2 TM batteries and 1 cranking battery, 10 or 15 amp per bank and what make?

3. Wet lead acid cell deep cycle marine batteries, what make?

Tom

It's not about what brand battery, it's about the battery's condition based on its use, charging , and maintenance.

 

If it's an old battery that has been performing well for years and now it isn't, and you've  maintained it the same way for years, and your fishing duty cycle has not changed, it's time for a new battery.  But charge it and take it to a dealer and have them do a load test on it.

 

If your use has changed, then it may be that the lakes you are now fishing don't give it time to charge on the motor's alternator.  Do you charge it between trips?  If not , you should.  Put it on a charger between trips.

 

You don't need a deep cycle, you need a starting battery.  But the brand is less important than its duty cycle, age, charging history, etc.

Quality only matters if you want it to last and be reliable, you rarely get more then you pay for with batteries. The OB engine size the OP is trying to crank is important.

AGM's require onboard charger designed to charge them, wet cell are very fore giving AGM's not so much.

If the boat has room for a larger cranking battery go up to 27, 29 or 31 depending on room for a tray.

The OP should be charging his batteries, all 3, at the end of the day with a good auto shutoff charger to aviod battery damage.He has a 3 bank charger that apparently isn't working correctly.

Tom